/*
 * test_ha_ctrlhello.c — Unit tests for handle_ctrlhello() (task 9.3).
 *
 * Tests exercise the primary-side OP_ctrlHello handler:
 *  - CtrlHelloRequest struct fields accessible (schema compile check)
 *  - CtrlHelloReply fields accessible (schema compile check)
 *  - handle_ctrlhello with malformed request returns -EINVAL
 *  - typemap fields: ctrl_hello_req_t and ctrl_hello_reply_t compile
 *  - OPCode_walCatchupEntry exists in generated capnp header
 *  - Request_body_ctrlhellomsg discriminant exists
 *
 * Full integration (WAL streaming, snapshot transfer) requires a live cluster
 * and is validated via make test-integration.
 *
 * Requirements: 6.5, 6.6, 6.7
 */
#define _GNU_SOURCE
#include <errno.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>

#include <unity/unity.h>
#include "controller.capnp.h"
#include "typemap.h"
#include "config_repl.h"

/* ── Test 1: CtrlHelloRequest struct is accessible from capnp.h ─────────── */
static void test_ctrl_hello_request_fields_accessible(void)
{
    /* Static compile check: access CtrlHelloRequest field constants */
    TEST_ASSERT_GREATER_THAN(0, (int)CtrlHelloRequest_struct_bytes_count);
    TEST_ASSERT_GREATER_THAN(0, (int)CtrlHelloRequest_word_count);
    printf("test_ctrl_hello_request_fields_accessible: PASS\n");
}

/* ── Test 2: CtrlHelloReply struct is accessible from capnp.h ──────────── */
static void test_ctrl_hello_reply_fields_accessible(void)
{
    TEST_ASSERT_GREATER_THAN(0, (int)CtrlHelloReply_struct_bytes_count);
    TEST_ASSERT_GREATER_THAN(0, (int)CtrlHelloReply_word_count);
    printf("test_ctrl_hello_reply_fields_accessible: PASS\n");
}

/* ── Test 3: ctrl_hello_req_t C struct compiles correctly ───────────────── */
static void test_ctrl_hello_req_t_layout(void)
{
    ctrl_hello_req_t req;
    memset(&req, 0, sizeof(req));
    req.name        = NULL;
    req.key         = NULL;
    req.applied_lsn = 42;
    req.config_tag  = 7;
    TEST_ASSERT_EQUAL_UINT64(42, req.applied_lsn);
    TEST_ASSERT_EQUAL_UINT64(7,  req.config_tag);
    printf("test_ctrl_hello_req_t_layout: PASS\n");
}

/* ── Test 4: ctrl_hello_reply_t C struct compiles correctly ─────────────── */
static void test_ctrl_hello_reply_t_layout(void)
{
    ctrl_hello_reply_t rep;
    memset(&rep, 0, sizeof(rep));
    rep.committed_lsn  = 100;
    rep.needs_snapshot = 0;
    rep.config_tag     = 5;
    TEST_ASSERT_EQUAL_UINT64(100, rep.committed_lsn);
    TEST_ASSERT_EQUAL_INT(0, rep.needs_snapshot);
    TEST_ASSERT_EQUAL_UINT64(5, rep.config_tag);
    printf("test_ctrl_hello_reply_t_layout: PASS\n");
}

/* ── Test 5: OPCode_walCatchupEntry exists in generated capnp header ────── */
static void test_opcode_walcatchupentry_exists(void)
{
    int opcode = (int)OPCode_walCatchupEntry;
    TEST_ASSERT_EQUAL_INT(37, opcode);
    printf("test_opcode_walcatchupentry_exists: PASS\n");
}

/* ── Test 6: Request_body_ctrlhellomsg discriminant exists ─────────────── */
static void test_request_body_ctrlhellomsg_exists(void)
{
    int disc = (int)Request_body_ctrlhellomsg;
    /* The body union discriminant is derived from @N in the capnp schema.
     * ctrlhellomsg @26 → discriminant 23 (0-indexed from @3, fields @3..@26). */
    TEST_ASSERT_GREATER_OR_EQUAL(0, disc);
    printf("test_request_body_ctrlhellomsg_exists (disc=%d): PASS\n", disc);
}

/* ── Test 7: handle_ctrlhello rejects request with wrong body_which ─────── */
static void test_handle_ctrlhello_rejects_malformed(void)
{
    /* NULL cluster — handle_ctrlhello checks body_which before dereferencing c */
    xce_request_t req;
    memset(&req, 0, sizeof(req));
    req.opcode     = OPCode_hello;
    req.body_which = Request_body_nomsg;  /* not ctrlhellomsg */

    int rc = handle_ctrlhello(NULL, NULL, &req);
    TEST_ASSERT_EQUAL_INT(-EINVAL, rc);
    printf("test_handle_ctrlhello_rejects_malformed: PASS\n");
}

/* ── Test 8: handle_ctrlhello rejects NULL body pointer ─────────────────── */
static void test_handle_ctrlhello_rejects_null_body(void)
{
    xce_request_t req;
    memset(&req, 0, sizeof(req));
    req.opcode             = OPCode_hello;
    req.body_which         = Request_body_ctrlhellomsg;
    req.body.ctrlhellomsg  = NULL;  /* body set but null payload */

    int rc = handle_ctrlhello(NULL, NULL, &req);
    TEST_ASSERT_EQUAL_INT(-EINVAL, rc);
    printf("test_handle_ctrlhello_rejects_null_body: PASS\n");
}

/* ── Suite entry point ──────────────────────────────────────────────────── */
void test_ha_ctrlhello(void)
{
    UNITY_BEGIN();
    RUN_TEST(test_ctrl_hello_request_fields_accessible);
    RUN_TEST(test_ctrl_hello_reply_fields_accessible);
    RUN_TEST(test_ctrl_hello_req_t_layout);
    RUN_TEST(test_ctrl_hello_reply_t_layout);
    RUN_TEST(test_opcode_walcatchupentry_exists);
    RUN_TEST(test_request_body_ctrlhellomsg_exists);
    RUN_TEST(test_handle_ctrlhello_rejects_malformed);
    RUN_TEST(test_handle_ctrlhello_rejects_null_body);
    UNITY_END();
}